An air barrier system for a building envelope can minimize energy consumption by inhibiting or preventing the flow of air from both sides (i.e. in and out). Different types of air barrier systems are presently in use as air and moisture barriers in building envelopes, such as mechanically attached membranes (.e.g. polyethylene film or Tyvek™), self-adhered membranes, closed cell and open cell spray-applied polyurethane foam and fluid applied membranes that cure to solid films (e.g. polymer-based coatings and paints).
Silicone polymer-based coatings are known to have resistance against UV radiation and other environmental factors. Elastomeric silicone coatings can repel liquid water by virtue of their hydrophobic nature but they can be permeable to water vapors. The permeability of water vapor can inhibit or prevent condensation of water vapor to liquid water inside the building envelope.
Silicone-based air and water barrier compositions are known. For example U.S. Pat. No. 8,513,328 discloses a one-part room temperature vulcanizing silicone-based air and water barrier composition comprising a silanol-terminated diorganopolysiloxane polymer, a metal chelate condensation cure catalyst and a polyalkoxysilane crosslinking agent. The composition of U.S. Pat. No. 8,513,328 can further optionally comprise a treated fumed silica reinforcing filler, a stearic acid treated ground calcium carbonate extending filler or a precipitated calcium carbonate filler and an adhesion promoter.
Other one-part room temperature vulcanizing compositions have also been disclosed for use in coating applications.
For example, U.S. Pat. No. 6,437,039 discloses a one-part room temperature vulcanizable (RTV) organopolysiloxane rubber composition of a particular formulation for use as a protective coating on surfaces. U.S. Pat. No. 6,833,407 discloses a solvent free one-part RTV organopolysiloxane rubber composition of a particular formulation for use as a high gloss surface coating. U.S. Pat. No. 6,878,410 discloses a method of protecting a surface from the effects of a fire using a one-part RTV polysiloxane composition which comprises one or more fire retardant fillers. U.S. Pat. Nos. 6,939,582 and 7,232,609 disclose one-part RTV organopolysiloxane rubber compositions of particular formulations for use as a coating on high voltage electrical insulators.